Fluid mechanics

[OP !okaN1spLpg No.2606059]

PhD student in fluid mechanics here. I'm hoping we have other people that know something about fluids that can throw out some ideas.

So check it: I know a lot about the mathematics of fluid mechanics-- it's fuckin complicated. And I know a lot about aeronautical engineering in application, what airplanes work, how they work, and why they work. But I feel like after 3 degrees, I'm still very unsure about many things in aerodynamics. Like, the very basic fluid flows, for example, what is the effect on the lead bird in a flying-V formation, and how does it change if the trailers are closer or farther away?

So I want to know if you know of any books on the qualitative side of aerodynamics... skip the ridiculous math, and show me some intuitive physical things about common flows. All I can give is van dyke's "album of fluid motion" which doesn't really give answers.

[OP !okaN1spLpg No.2606075]

Also interesting: if two bodies (say birds, flags, cars, airplanes, whatever) are following each other.... if the lead body is rigid, it'll experience higher drag and the trailer will experience lower drag (basic drafting you see in cars or cyclists), but if the body is flexible, the leader will actually experience lower drag and the trailers will experience higher drag.

the more i learn about fluid mechanics the more my brain is full of fuck. i'm close to finishing a phd and i just keep feeling dumber.

[Anonymous No.2606086]

>>2606075
The shit? How does the leader receive lower drag?

[Anonymous No.2606096]

>>2606086
FUCK, man don't ask him to explain it his mind is already full of fuck as it is

[Anonymous No.2606093]

no idea but bump

[OP !okaN1spLpg No.2606105]

>>2606086
see dude, that shit is full of fuck. mathematical idea: low speed flow is very elliptic, and stuff behind you affects stuff ahead of you (action at a distance). you can measure the drag of an object by analyzing it's wake a long distance behind it (fact). an object behind the leader can break up the wake and actually result in lower drag for the leader. fluid mechanics is fucking crazy, son.

>>2606096
seriously, i'm hating life. i get paid money to do research in this shit and i keep getting more and more confused. i have no fucking idea what's going on. i "smile and nod" like i'm a fucking mexican immigrant at these meetings.

[Anonymous No.2606123]

Figuring out fluid mechanics is one of the most sought after answers in many fields of science. There are probably people who have spent their entire lives studying fluid mechanics and feel the exact same way you do.

[Anonymous No.2606128]

>>2606105

Spend some time going back through the basics, building intuition. I've found that there's not just intuitive explanations for things lying around, that's exactly what you're trying to form yourself as you gain mastery. Do you have old notes or books on the foundations that you can look through? If you're anything like me, your second trip through material you know will be a refreshing experience, since you'll really see how far you've come in understanding, and be in a setting where your "learning new stuff" isn't being taxed so much so more understanding and connections can be built.

Basically, the first time I go through some math I can follow the motions, the second I can follow the ideas, and once I've seen more complicated stuff and come back, I can follow the connections to the new shit I'm still struggling with.

[Anonymous No.2606132]

>>2606075
well all the information you remember will eventually fit the big picture

interesting stuff about flexible bodies i didn't know that

it's just my suggestion i'm no scientist neither is this my field but just like with cars the closer they are the less drag they feel
i've even heard that at nascar and formula 1 teammates drive one after the other to save fuel
they go just as fast but at lower rpm

so i guess it should be the same with airplanes
the first plane feels most drag but then there is no cyclone sucking it backwards
whereas the the plains at the rear of the formation don't feel the frontal drag, they fly in the lower pressure bubble behind the first but feel the sucking force from the cyclones forming
for the most optimal distance between them and less drag you should do the math

[OP !okaN1spLpg No.2606133]

>>2606123
that's not the fuckin point, holmes. a lot of phenomena is well understood. sure, we haven't solved N-S, but smart people can qualitatitvely tell you the result of complex configurations a priori.

i'm accomplished (and published) in the field. i can work through the unsolvable equations of motion as well as anyone. the problem is bridging the gap from that academic quality to being a great engineer.

[Anonymous No.2606137]

>claim to be a phd student in a topic
>go to 4chan for recommendations for literature on the topic.

You dont have to lie to us OP. Just say you are an engineering student who is in fluids right now and wants to learn some stuff.

[Anonymous No.2606153]

>>2606105
OP just do what they tell you to do.. lol as long as you can do that you should be ok. if you get fired sometime at least you got as much money out of it as you could XD

[Anonymous No.2606154]

You should go fly an airplane. Usually introductory flights are around $100 (of course that assumes you live in America, where we have airplanes. If not, an airplane is a vehicle that allows humans to fly. Google it.)

[Anonymous No.2606159]

Just curious OP, what department do you work in?

[OP !okaN1spLpg No.2606171]

>>2606128
fair idea, i wonder how far you've taken it... but yes, after several years of grad study, i'm impressed by my own ability to quickly handle the quantitative stuff that used to trouble me. but i'm used to that now... i'm frightened by no math. i'm at a high end university, and i enjoy being taught by very impressive scientists.

i don't care about following the motions anymore. i want to be legitimately better than those around me.

[OP !okaN1spLpg No.2606192]

>>2606137
i have two masters degrees and a bachelors in aerospace engineering and i'm currently finishing my phd. go fuck yourself. i've taken probably 15 fluids courses at this point. i'm not asking for homework help.

>>2606153
only good suggestion so far. i have learned a ton from the mere 5 hours of flight training i've had. it's very awesome how humbled you can feel after taking years of fluid mechanics, and then feeling helpless on a runway.

>>2606159
aerospace engineering, holmes.

[Anonymous No.2606218]

>>2606171

How long have the very impressive scientists been doing what they are, as compared to you? Do you see yourself being as good as they were when they were in your shoes? I have a feeling that having 30 years experience on you might explain why they have a better feel for things.

[OP !okaN1spLpg No.2606249]

>>2606218
>How long have the very impressive scientists been doing what they are, as compared to you? Do you see yourself being as good as they were when they were in your shoes? I have a feeling that having 30 years experience on you might explain why they have a better feel for things.

totally. i use that as justification a lot. but i still recognize a big gap between how i learn and how they learned. i write research papers and i can't imagine how i'd do it without google scholar. yes they have a shitton of experience on me, so naturally theyr'e going to be smarter on all these topics. i'm younger, and i'm particularly amazing and coming up with computational solutions in very short order. but for respect from these guys, i need to know everything they do about analytical fluid mechanics, plus be a badass in software.

sometimes i feel confident... they knew more about certain things when they were my age than i do, but i'm really really good at the more modern stuff.

[Anonymous No.2606264]

>>2606249

I don't see what the problem is. You have an edge over the older generation and can contribute to the field in a new way. Why try to master what they've already done when you can apply your own skills to take things in a new direction?

[Anonymous No.2606304]

My god, I am retarded.

[Anonymous No.2606319]

HAHAHA HAHOAHA HOAHOAHOAOHOAHOAHAO

OP HOW DO YOU LIKE THIS SHIT

[Anonymous No.2606320]

>>2606059
>PhD student in fluid mechanics here
You wish

[Anonymous No.2606322]

[OP !okaN1spLpg No.2606332]

>>2606264
because there isn't a "new direction" per se. yeah, i know a lot about where research is going in this field. but the problem is, those older people didn't do anything wrong. i literally have to know EVERYTHING from fluid mechanics from all of humanity in order to publish my work. every analytical, experimental, and computational aspect, i have to know it. that's fuckin stressful.

it's not like physics where you can masturbate out a new equation. we have to give theories that fit all old data and correctly predict present phenomena.

[OP !okaN1spLpg No.2606339]

>>2606320
okay dropout. go read some more wikipedia physics question while the rest of with actual college degrees discuss things.

[Anonymous No.2606342]

If I'm 20, is it basically impossible for me to switch paths and work on fluid dynamics?

[OP !okaN1spLpg No.2606357]

>>2606342
>If I'm 20, is it basically impossible for me to switch paths and work on fluid dynamics?

what? no. i was 22 before i even knew what "computational fluid dynamics" was, and now i'm getting paid to get a phd in it.

[Anonymous No.2606367]

Fuck, looks like i'm late to the discussion. Fluids was my favorite class in undergrad

[Anonymous No.2606380]

>>2606332
I know that feel, OP. I do control theory and it seems like the last "big thing" was back in 1979 and since then it's just been applying it to different scenarios. It's like in order to make a significant contribution to the field you need to know absolutely everything about controls (and obviously be well versed in lin alg, variational calc, complex analysis, and a few others).

Fluid dynamics is awesome though. I took a grad level class in it as an undergrad and it blew my mind, but it was a lot of fun.

[Anonymous No.2606381]

I love fluids! I'm glad people here have the same fetish as me!

[Anonymous No.2606382]

>>2606059
ever heard of hot quark soup op?

[Anonymous No.2606386]

Hey OP, has Navier Stokes been solved yet? get on that.

also, let's talk about boundary layers and oblique shocks

[Anonymous No.2606462]

Check out this animation from Wikipedia's article on the Reynolds Number.

[Anonymous No.2606468]

lol o forgot the image

[Anonymous No.2606484]

Samuel L. Jackson on fluid dynamics:

http://www.youtube.com/watch?v=M78-7aqXGOA

[Anonymous No.2606517]

fluid is for faggots

[Anonymous No.2606528]

OP, I recommend this.

[Anonymous No.2606543]

How come there three different scientific models for the superfluidity of liquid helium?

[Anonymous No.2606564]

>>2606468
it looks like it's alive and swimming lol

[Anonymous No.2606574]

>>2606059
>PhD student in fluid mechanics

Is that real fluid mech (a physics Phd), or some shitty engineering shit?

If you are an engineer, it would explain why you feel like you don't know shit (cause you don't know shit!).

[Anonymous No.2606576]

>>2606468
I have no idea what's going on in this thread, but that's pretty.
Dat symmetric chaos.

[Anonymous No.2606612]

http://www.youtube.com/watch?v=LvVuuaqCC7A

Work for golf ball companies - give golf balls to CEOs

PhD in Fluid Dynamics
Any job you want (as long as the CEO plays golf)
300k starting

[Captain Midnight No.2606748]

refer to the forgotten science of analog computing simulation

http://www.analogmuseum.org/english/examples/lfsim/

[Anonymous No.2606806]

OP if you are still here wasnt there some paper that came out a while ago that demonstrated you could get a turbulent flow in a tube to go back to laminar given a long enough length and correct conditions?

[OP !okaN1spLpg No.2608112]

>>2606380
cool, i love controls. i think fluids people and controls people mesh very well... both tends to find the other field very interesting. there's a lot of very cool crossover work too.

>>2606528
thanks for trying, i've been through that book (it's okay) but i don't really need an intro to CFD, as that's my field. what i'm specifically after is a qualitative text on fluid mechanics. like if van dyke's album had a bit more description of the relevant phenomena in the images.

[OP !okaN1spLpg No.2608120]

>>2606612
yeah i know those people. same field... boring application.

>>2606806
not sure if there's a specific paper you're referring to, but that's a well known idea in turbulent fluids. you can make a laminar flow go turbulent by an adverse pressure gradient; you can also make a turbulent flow go laminar by a favorable pressure gradient.

[Anonymous No.2608166]

fuck yeah fluid dynamics

I'm doing something similar... just in super fluid helium.

[Anonymous No.2608227]

I've got these eBooks on my hard-drive OP:

Fluid Dynamics for Physicists - Faber, T.E..djvu
Fluid Mechanics 2nd ed. - P. Kundu, I. Cohen.pdf
Fluid Mechanics 4th ed - F. White.pdf
Foundations of Fluid Mechanics - G. Gallavotti (2000) WW.pdf
Liquids and Gases - Principles of Fluid Mechanics [elementary txt] - P. Fleisher (2002) WW.pdf
Drugs of Abuse - Body Fluid Testing - R. Wong, H. Tse (Humana, 2005) WW.pdf
Graebel - Advanced Fluid Mechanics (AP, 2007).pdf
Johnson - Fluids and Electrolytes Demystified [medical] (McGraw, 2008).pdf
Hoffman - Computational Fluid Dynamics [Vol 1] 4e (EES, 2000).pdf
Hoffman - Computational Fluid Dynamics [Vol 2] 4e (EES, 2000).pdf
Petrila - Basics of Fluid Mechanics and Intro to Computational Fluid Dynamics (Springer, 2005).pdf
Shaughnessy - Introduction to Fluid Mechanics (Oxford, 2005).pdf


Would any of these help? I'll upload one for you, if you want.

[Inurdaes !V1sPhobos. No.2608236]

http://www.51cnnet.net/directory
http://ebookee.org/
http://ebooklink.net/g/home/
http://avaxhome.ws/ebooks
http://www.filestube.com/
http://pdf-search-engine.net/
http://www.warez-bb.org/
http://free-books.dontexist.com/
http://gen.lib.rus.ec/
http://bib.tiera.ru/static
http://manybooks.net/
http://www.pdfqueen.com/
http://www.gutenberg.org/wiki/Main_Page

[OP !okaN1spLpg No.2608267]

>>2608227
thanks... but i have a bookshelf full of fluid mechanics textbooks, and a pretty good knowledge of the underlying math and science (good enough to pass phd general exams anyway). i'm looking for a *qualitative* book. light on the math end, heavy on the "here are some complex flows, and here are the interesting things about them you should look at" end.

i'm not certain such a text even exists.

[OP !okaN1spLpg No.2608290]

http://www.amazon.com/Simple-Science-Flight-Insects-Jumbo/dp/0262700654/ref=pd_sim_b_4

googling around, mind pick up this book... the author wrote a very famous text on turbulence...

[None !okaN1spLpg No.2608781]

Transition of free jet (upper) and wall jet (lower) at varying reynolds numbers.